diff --git a/backdoor/helper.h b/backdoor/helper.h
new file mode 100644
index 0000000..18b53ac
--- /dev/null
+++ b/backdoor/helper.h
@@ -0,0 +1,21 @@
+/*
+ * Helpers for instruction-based backdoor communication.
+ *
+ * Copyright (c) 2010 Lluís Vilanova
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see .
+ */
+
+DEF_HELPER_1(backdoor_i8, void, i32);
+DEF_HELPER_2(backdoor_i8_v, void, i32, tl);